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XIII. " Report of Proceedings of the Astronomical Expedition 
to Teneriffe, in 1857." By Prof. C.Piazzi Smyth. Pre- 
sented by G. B. Airy, Esq., F.R.S., Astronomer ' Royal. 
Received June 2, 1857. 


The Report, presented originally to the Admiralty, at whose ex- 
pense and whose orders the Expedition was sent out, consists of ten 
parts, with their contents as follows : — 

Part 1. Astronomical and Phvsical observations. 

Part 2. Mountain Meteorological Journal. 

Part 3. Reductions of above. 

Part 4. Sea-level Meteorological Journal. 

PartS. Reductions of above. 

Part 6. Plans, Sections, and Astronomical illustrations. 

Parts 7, 8, 9. Condensed statement of results and conclusions in 
Astronomy, Physics, Meteorology, Geology, Botany, and Navigation, 

Part 10. Photographs illustrating the botany and geology of three 
different levels in the Island. 

The original instructions of Prof. Piazzi Smvth had been purely 
astronomical, and were to ascertain how much telescopic vision could 
be improved by eliminating the lower third of the atmosphere. In 
furtherance of this view, he erected the Sheepshanks equatorial of 
the Edinburgh Observatory on Mount Guajara in Teneriffe at a 
height of 8903 feet, and found the space-penetrating power ex-? 
tended from mag. 10 to mag. 14, and so great an improvement in 
definition, that a magnifying power of 240 could be used with more 
satisfaction on the mountain, than one of 60 in Edinburgh. After 
a month's experience of this station, he ascended to a higher one— 
the Alta Vista — at a height of 10,702 feet on the eastern slope of 
the Peak, and there erected the large equatorial of Cooke, lent for 
the occasion by Mr. Pattinson of Newcastle. The definition was here 
admirable, and the telescope equal, if not superior, to all the test 
objects it was turned upon. A comparative hypsometric estimate 
was not possible; for although the observer had spent an equal 
number of days to what he employed on the Peak, in trying to as- 
certain the capabilities of the instrument at the house of its hospi- 


table owner, on several visits, the cloudy atmosphere of Newcastle 
had always prevented any good observations being made. 

An argument in favour, however, of the increase of height was 
ascertained through means of radiation instruments, which indicated 
almost as much improvement between 10,700 and 8900 feet, as be- 
tween the latter height and the sea-level. This unexpected degree 
is attributed by the author to the circumstance of the highest station 
being almost clear of certain dry, hazy, or dusty strata of atmo- 
sphere, which include and overtop the intermediate station, and are, 
next to the clouds themselves, the greatest obstacle to good telescopic 
vision of the heavenly bodies. The results with regard to the 
clouds were equally satisfactory, for ^ths of the whole were found 
to be under the level of 5000 feet. 

The author expresses the most cordial thanks to Sir Charles 
Wood, the First Lord of the Admiralty, for his intelligent liberality, 
to which the Expedition owed its existence ; also to Lord Clarendon, 
the Secretary of State for Foreign Affairs, for his letters to the 
Spanish Government and to the English Customs ; and he acknow- 
ledges with pleasure the amount of assistance which he received 
from many private gentlemen, friends of science, through whose 
contributions he was enabled to execute, with a limited grant, and 
in a circumscribed portion of time, a much greater amount of work 
than he could otherwise have hoped for ; those gentlemen were, 
Robert* Stephenson, Esq., M.P., G. B. Airy, Esq., H. L. Pattinson, 
Esq., Dr. J. Lee, Prof. Stokes, the late Admiral Beechey, Admirals 
FitzEoy, Manners and Smyth, Prof. Baden Powell, J, Gassiot, Esq., 
Capt. Washington, and Messrs. Cooke and Adie. 

In the island of Teneriffe, Prof. Piazzi Smvth also received va- 
luable aid in many ways from C. Smith, Esq., of Orotava, formerly 
of Trinity College, Cambridge, L, Hamilton, Esq*, of Santa Cruz, 
Don Francisco Aquilan, Spanish engineer, and more particularly 
from the acting Vice-Consul of Orotava, Andrew Goodall, Esq., and 
his nephew Mr. Carpenter, who were aiding and abetting, and in 
fact forming an important part of the Expedition during its whole 
stay in Teneriffe.